Britannia is the ancient personification of the spirit of Britain, and is traditionally depicted with a trident, shield, and helmet. The image of Britannia first appeared on Roman coinage, as early as 119 AD in the reign of Emperor Hadrian. She was revived on coinage in 1659 by Charles II of England in 1672, and has appeared on British coinage ever since.
When the United Kingdom resolved to produce a bullion investment coin in 1987, Britannia was the obvious choice for a design that would immediately be identifiable as British. The silver Britannia debuted in 1997, in 958 fineness "Britannia silver." These 1997-2012 coins have an actual silver content of 1 troy ounce, with the remaining 0.043 oz in copper. The designs on the silver Britannia during this time alternated between the original design and custom alternative designs.
For 2013 onward, it was decided to increase the purity of the Britannia to 999 fineness (99.9% pure silver) to match the silver bullion coins of other nations.